Not a trace of Don; What's next?

Tropical Storm Don, the fourth named storm of the 2011 season, made landfall near Baffin Bay, Texas yesterday evening around 10pm CDT in less-than-grand fashion. The storm was looking very weak for the 24 hours before landfall, but fizzled rapidly after landfall, and by early Saturday morning, there was barely a trace of the storm to show that it even existed in the first place.

NHC Hurricane Specialist Eric Blake probably said it best in this mornings 5am EDT discussion on the storm:

THE DON IS DEAD. THE CYCLONE LITERALLY EVAPORATED OVER TEXAS ABOUTAS FAST AS I HAVE EVER SEEN WITHOUT MOUNTAINS INVOLVED. DON HAS NOCONVECTION...MEAGER RAINFALL...AND ONLY A SLIGHT SIGNATURE INSURFACE OBSERVATIONS AND RADAR DATA. THEREFORE...THIS IS THE LASTADVISORY ON THIS SYSTEM.

Figure 1. Total precipitation accumulation for the storm, estimated by radar.

The heaviest rainfall was falling south of the storm's center yesterday, so it wasn't surprising that Brownsville saw the most rain, 0.63 inches. KBRO also recorded 18 mph wind gusts. But to the north of the center, where many of the media were located, not a drop of rain fell. Corpus Christi saw zero inches of rain, but did record gale-force wind gusts (39 mph). Harlingen, near Baffin Bay, and close to where the center made landfall, saw 0.20 inches of rain and 18 mph wind gusts. This storm did very, very little to relieve any drought conditions in Southern Texas. And so it continues.

What's next: Invest 91L continues to impress

Invest 91L, which is located near 12°N 48°W in the central Atlantic, continues to impress today, and has shown signs of more organization over the past 24 hours. 91L will probably develop into a tropical cyclone before it reaches the Lesser Antilles, so residents of these islands should remain watchful and prepared. Satellite loops show not only organized thunderstorm activity, but also the makings of a surface circulation. Something this wave has working against it right now is dry air—there's a large mass of Saharan air on the north and east sides of the system, which could at least prevent significant intensification. Also, University of Wisconsin CIMSS analysis shows some strong wind shear (30-40 knots) to the north of the wave. However, I don't expect this to prevent development of the wave. Wind shear out ahead of the system is relatively low (5-15 knots). Moisture is plenty high within the system, and sea surface temperatures are warm and toasty (28°C+) and will only get warmer as 91L moves west into the Caribbean.

Figure 2. Infrared satellite of invest 91L taken at 1:15pm EDT today.

Forecast for 91LMost of the reliable forecast models (GFS, CMC, FIM, and the ECMWF) have come to agree that 91L will develop, however, they differ on how long-lived that will be. Some of the models are suggesting it will be a short-lived tropical cyclone, not making it out of the Caribbean alive, and some suggest that it will hold together and intensify as it moves north of the Caribbean islands. The forecast track for the system will most likely be to the northwest through the Caribbean, at which point it will take a northeast turn near the Bahamas, never reaching the U.S. coast. HWRF agrees with this track (and also brings the system to category 2 strength by August 3rd). However, there is still some uncertainty that the system could track west, south of the Caribbean islands, and potentially into the Gulf of Mexico. However, none of the models that suggest this solution actually show that the wave will be a tropical cyclone at that point.

The National Hurricane Center is giving this wave an 80% chance of developing into at least Tropical Depression Five over the next 48 hours. Chances are we will see Emily out of this system. A Hurricane Hunter mission is scheduled for tomorrow at 2pm EDT, but I wouldn't be totally surprised to see them call this system this evening, given the threat to the Lesser Antilles.

Watching a northwest Caribbean disturbance

A broad area of disturbed weather is producing some heavy thunderstorms in the northwest Caribbean, southeast of the Yucatan Peninsula. Little to no low-level circulation exists with this feature, and none of the models are picking up on it. The Hurricane Center has "blobbed" this item (as I like to say) with a "near 0%" chance of developing over the next 48 hours. This disturbance could cause major flooding in the region given the amount of thunderstorm activity, and predictability for systems like this (potential Bay of Cempeche tropical cyclones) is very low. Models have a short lead time on development, and they spin up very fast once they enter the Bay of Campeche given the favorable topography of the land surrounding it. The difference between this system, though, and one like Arlene, is that there is very, very little low level circulation already present. Pre-Arlene was a bit more organized before it crossed the Yucatan, and so it's hard to imagine that this disturbance will be able to hold together, should it get that far.

I think 91L will take a track similar to Don , maybe even a tad further south, 91L is moving slightly south of due west at about 260-265 degree , at least in my opinion it looks that way on vis sat loops, I think 91L will probably become Emily before the day is through also.Link

Quoting Neapolitan:I believe the 'L' in the model names stands for "lucreto". ;-) I asked him/her yesterday how it was possible for a "purely experimental" model that has aboslutely no internet presence to be operational in the real world in just two or three years. No response...

You don't use phase diagrams to determine if this is a tropical cyclone. We know this is warm core, but this doesn't mean we have a tropical cyclone on the Euro. The area of vorticity being shown on the Euro is simply that, vorticity. It doesn't even have a closed isobar associated with it.

Quoting Neapolitan:I believe the 'L' in the model names stands for "lucreto". ;-) I asked him/her yesterday how it was possible for a "purely experimental" model that has aboslutely no internet presence to be operational in the real world in just two or three years. No response...

Heheh. Unfortunately there are people in here who seem to believe lucreto's "models".

Just so everyone knows, these appear to be made-up models, as it seems only lucreto knows of their existence. I have yet to find a mention of them on Google.

I believe the 'L' in the model names stands for "lucreto". ;-) I asked him/her yesterday how it was possible for a "purely experimental" model that has aboslutely no internet presence to be operational in the real world in just two or three years. No response...

After watching years of Computer Model Runs as a Student showing Miami or South Florida get hit by a Category 3,4,5 and None of it Materializing ... I am almost sure it wont happen....

Although the Models are currently showing Florida getting hit... Intill we get a better fix on the storm.. I Wont take it seriously....

Yet... On the Other Hand... The Models have Consistently had their aim on Florida... and As Weatherguy3 explained in his video... the Alley this system will go will be influenced by a High in the Gulf and the Azores High... The "Squeeze" happens to be above Florida or above the Bahamas.

Once/If it makes it to the Bahamas and sit's in that warm water... i think it has a low chance of making it to hurricane status.

You really contradict yourself on this stuff. Not trying to be a jerk or anything. However, you dog the models for showing a landfall in Florida, but then you reference someone who is using models for their forecast to back up your statement.

The very broad center of this is near 12.5N and almost 60W.. moving just north of due west or 280deg.There is a midlevel vortex in the decay T-Storm cluster around 13.8N and 57.5W

2 Things I want to post here.

1. Most of the models really didnt project this to become defined and more developed until later tonight or on Tuesday once it passed thru the islands.

2. I feel the convection needs to form around 13N and 60W this evening around the broad center for thisto develop moreso...otherwise if this is not developed by Tuesday evening,..history says systems dont likegetting developed in the central carribean till they get past 75W.

Quoting MississippiWx:At this time, no development at all is something to really consider. If that's the case, a lot of weight will have to be given to the European for the next system we have as the EURO has been against developing this system basically the entire time. It sporadically showed 91L becoming a tropical cyclone, but it has kept it weak for the majority of the time.

Goodmorning to all i just came checking and i see a few of the computer models hitting se fl is this a continual trend that the models will just keep advaancing to the left and might not ever come north.....Am in the hollywood beach area so quite concerned

If you're killing time and can do your own contouring, nrt-700mb heights from Gonzo's flight. Disregard the obs number in front of some of the heights. Possibly suggest a stronger ridge N of the big islands but soft enough to allow a movement slightly N of W in the Caribbean.

click to enlarge

i have google earth app on my xoom pad,the files from tropicalatlantic are appaerntly unreadable,anyone get the hh on google earth with ur ipad or android os,me no luck:(

At this time, no development at all is something to really consider. If that's the case, a lot of weight will have to be given to the European for the next system we have as the EURO has been against developing this system basically the entire time. It sporadically showed 91L becoming a tropical cyclone, but it has kept it weak for the majority of the time.

Quoting nrtiwlnvragn:Looking back at dropsonde data (Google Earth) from the GIV jet yesterday did show some dryier air to the north.

If you're killing time and can do your own contouring, nrt-700mb heights from Gonzo's flight. Disregard the obs number in front of some of the heights. Possibly suggest a stronger ridge N of the big islands but soft enough to allow a movement slightly N of W in the Caribbean.

It's hard to say these solutions are highly unlikely when they are becoming the consistent solution. The reason that is becoming a popular solution in the models is the fact that 91L can't make up its mind and develop.

MississippiWx...

After watching years of Computer Model Runs as a Student showing Miami or South Florida get hit by a Category 3,4,5 and None of it Materializing ... I am almost sure it wont happen....

Although the Models are currently showing Florida getting hit... Intill we get a better fix on the storm.. I Wont take it seriously....

Yet... On the Other Hand... The Models have Consistently had their aim on Florida... and As Weatherguy3 explained in his video... the Alley this system will go will be influenced by a High in the Gulf and the Azores High... The "Squeeze" happens to be above Florida or above the Bahamas.

Once/If it makes it to the Bahamas and sit's in that warm water... i think it has a low chance of making it to hurricane status.

Back for spot-check. No TD yet. Overall conditions on the Atlantic side full of life though at the moment. If you look at the "big picture" rainbow look, 91L looks a comet streaking into the Caribbean, and that blob of convection over Florida looks like another comet streaking into the Gulf. .....Looks like a bad movie.